"As a result of the crash, both vehicles ended up on the right shoulder where the Tacoma overturned on its side," the CHP said.

Pontarolo suffered cuts to her face, arm and foot. Shakespeare complained of pain in her back.

The preliminary investigation listed the incident as a traffic collision. But if more evidence determines that it was intentional, "separate charges would follow," including possible attempted murder or assault with a deadly weapon, the CHP said.